1. Field of the Invention
The present invention relates to a hydraulic shock absorber.
2. Discussion of the Background Art
A conventional hydraulic shock absorber for vehicles disclosed in Japanese Patent Application Publication (JP-B) No. 5-26050. The hydraulic shock absorber comprising a cylinder; a piston rod which is inserted into the cylinder; a piston which is connected to an end portion of the piston rod inserted in the cylinder while including a damping valve, and which partitions the cylinder into a rod-side chamber where the piston rod is received, and a counter rod-side chamber where the piston rod is not received; a base piston which is fixedly provided on the counter rod-side chamber, and includes a damping valve; a sub-cylinder which is communicated with a side opposite to the piston and between the base piston in the counter rod-side chamber of the cylinder, and a free piston being movably received in the sub-cylinder. The conventional hydraulic shock absorber is constructed in a manner that a hydraulic fluid is inserted into the cylinder side of the free piston of the sub-cylinder, and a counter cylinder side of the free piston of the sub-cylinder is defined as a gas chamber.
In the prior art, a case end is welded to an end portion of a cylinder formed of a straight pipe, and the case end is formed with a closed recess portion having a stepped portion at the inner part thereof. A base piston is abutted against the stepped portion of the case end, and is fixed by means of a come-off preventive member attached to an opening side of the closed recess portion.
The following problems exist in the prior art.
(i) The base piston is fixed in a state of being abutted against the closed recess portion formed in the case end; for this reason, there is a need of subjecting the case end to a complicate processing. PA1 (ii) For the free piston to receive in the cylinder in addition to the base piston, the free piston must be received in the most inner part of the closed recess portion formed of the case end of the cylinder. For this reason, the inner face of the closed recess portion formed in the case end must be subjected to a complicate processing to securing slidability of the free piston.